I figure you go back far enough I am descended from Charlemagne. After all there were only about 200 million people back then, he has a lot of descendants.
You would be correct.
It has been estimated that everyone with even a drop of European blood is well over 99% likely to be a descendant of Charlemagne.
Even if some few are not, their likely mate is over 99% likely to be one, so their children will be.
Anyone who has children who have children who have children - eventually becomes the ancestor of a large % of humanity.